Calls useful for debugging the hvbox layout

/* name is not copied or free'd */ MBTK_INLINE void mbtk_dbg_widget_set_name(mbtk_widget_t *w, const char *name); /* Print the hvbox tree of the whole window w is in */ MBTK_INLINE void mbtk_dbg_widget_dump_tree(FILE *dst, mbtk_widget_t *w); /* Print the hvbox subtree starting from w */ MBTK_INLINE void mbtk_dbg_widget_dump_subtree(FILE *dst, mbtk_widget_t *w);